title: Effects of Ureaplasma urealyticum lipid-associated membrane proteins on rheumatoid arthritis synovial fibroblasts.
abstract: OBJECTIVE
  As an infectious agent might play a role in rheumatoid arthritis (RA) development, this study investigated effects of Ureaplasma urealyticum lipid-associated membrane proteins (UuLAMPs) on RA synovial fibroblast (RASF) proliferation, and tumour necrosis factor (TNF)-α and interleukin (IL)-1β production by THP-1 macrophages. Possible immunogenic proteins in UuLAMPs were identified.
  
  
  METHODS
  RASFs were cultured from synovial tissue from donors with RA. Serum samples from donors with/without RA and with/without U. urealyticum infection were used for immunogenicity analyses. THP-1 macrophages served as a model for synovial macrophages. TNF-α and IL-1β mRNA levels were assessed using reverse transcription-polymerase chain reaction; protein levels were estimated using enzyme-linked immunosorbent assay. UuLAMPs underwent separation and Western blot analyses.
  
  
  RESULTS
  UuLAMPs (0.025-0.4 µg/ml) stimulated RASF proliferation in a dose- and time-dependent manner, and increased TNF-α and IL-1β levels in THP-1 macrophages. Several immunogenic UuLAMPs were identified, but antibodies to a 25 kDa protein were only found in RA patients with U. urealyticum infection.
  
  
  CONCLUSIONS
  UuLAMPs might induce RASF proliferation and proinflammatory cytokine secretion in synovium from RA patients. A 25 kDa U. urealyticum protein might act as a cross-reactive antigen.
authors.affiliation: Department of Rheumatology, Provincial Hospital Affiliated to Shandong University, Jinan, China.
authors.forename: Min
authors.initials: M
authors.lastname: Fu
authors.forename: Li Hui
authors.initials: LH
authors.lastname: Chen
authors.forename: Guangtao
authors.initials: G
authors.lastname: Xia
authors.forename: Yuanchao
authors.initials: Y
authors.lastname: Zhang
mesh_terms: D000328:Adult; D000942:Antigens, Bacterial / Q000276:immunology*; D001172:Arthritis, Rheumatoid / Q000150:complications / Q000276:immunology / Q000382:microbiology / Q000473:pathology*; D001426:Bacterial Proteins / Q000302:isolation & purification / Q000494:pharmacology*; D002460:Cell Line; D049109:Cell Proliferation / Q000187:drug effects; D005260:Female; D005347:Fibroblasts / Q000187:drug effects* / Q000276:immunology / Q000473:pathology; D006801:Humans; D007106:Immune Sera; D053583:Interleukin-1beta / Q000096:biosynthesis / Q000276:immunology; D008264:Macrophages / Q000166:cytology / Q000187:drug effects / Q000276:immunology; D008297:Male; D008875:Middle Aged; D061251:Primary Cell Culture; D011510:Proteolipids / Q000302:isolation & purification / Q000494:pharmacology*; D013583:Synovial Membrane / Q000276:immunology / Q000382:microbiology / Q000473:pathology*; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis / Q000276:immunology; D016869:Ureaplasma Infections / Q000150:complications / Q000276:immunology / Q000382:microbiology / Q000473:pathology*; D016990:Ureaplasma urealyticum / Q000737:chemistry / Q000276:immunology*
chemical_list: D000942:Antigens, Bacterial; D001426:Bacterial Proteins; D007106:Immune Sera; D053583:Interleukin-1beta; D011510:Proteolipids; D014409:Tumor Necrosis Factor-alpha
keywords: Cross-reactive antigen; cytokine expression; lipid-associated membrane proteins; rheumatoid arthritis; Ureaplasma urealyticum